Field of the Invention
The present invention relates to hydraulic systems and power generation systems. In particular, the present invention relates to a conversion system, which converts the energy of various types to water pressure, followed by collection, normalization, accumulation, distribution, storage and utilization of this pressure, in order to perform useful work, such as, for example, electric power generation.
Description of the Related Art
To produce useful work on a commercial scale, it is necessary that generation volume is the same order of magnitude as what the consumer uses. Modern industry is based on national and transnational power grids, which have morning and evening peaks in populated areas, and constant or daytime load from industrial consumers. Today's technological equipment is calculated for the respective operating power sources, rated in the order of tens or hundreds of kilowatts and above.
Flow generators (wind and hydro-generators of various designs) can have a wide range of characteristics, including size, but with increase of their size, their inertia also increases. High inertia makes most of these structures operable only at a relatively strong flow of liquid or air, which is able to exceed their own inertia. This feature reduces the ratio of time in which the generator produces energy to the total working time.
A typical ocean wave has an amplitude range order of few meter or less, and the period on the order of several seconds. The main part of the wave energy is in the fluctuation of vertical surface. Generators that utilize the fluctuation of water surface theoretically cannot be effectively equipped with a working body (floats) with dimensions of more than half of the wave period due to dampening (skirt) the wave itself, losing the efficiency of its use.
For the above reasons, the most promising operating mechanisms for the industrial purposes are sufficiently lightweight mechanisms that allow capturing the energy impact of the least natural disturbances at the maximum level. As a result, these mechanisms will have a small useful output from single mechanism, therefore multiple units will create arrays for energy extraction from natural phenomena. In addition, various natural phenomena may occur in the same geographic location at different (including overlapping) time intervals, which makes it reasonable to use sufficiently versatile energy collection systems.
Currently, all known methods of electric power generation using the power of permanent or periodic motions of natural masses in marine areas are divided into two broad classes:
1. Systems of direct power generation on the system itself in the place of installation
2. Systems based on transporting volumes of water from the natural water bodies to the target engines.
Systems of the first type have two design disadvantages:
The presence of electrical equipment immediately adjacent to the working body in the area of the ocean that (taking into account the electrical conductivity of sea water) requires to equip them with a variety of safety systems, which leads to complexity of such systems and increases the cost of their construction and maintenance; and
Instability of the power generation results in the need for the collection and distribution systems, which also complicates the construction of distributed systems of this type.
Systems of the second type operate installations of a single working mechanism, which makes it necessary to use a system of pipes and/or hoses for the delivery of pumped liquid to the place of its utilization. Bernoulli's Law introduces significant unproductive losses of energy in the pipes/hoses, which greatly reduces the effectiveness of such systems.
For example US2005034452 discloses a pumped-storage system that uses gravitational force of downward movement of large amounts of water for conversion into electrical energy. In a preferred embodiment, the system uses an artificial lake. Although at greater height difference, performance can be higher, it is sufficient if the lake is located at a height of between twenty to thirty feet. The lake, which may exceed one hundred acres in size, can be located above and adjacent to the natural water bodies (for example, it can be located on the coast line of the ocean). Sandy soil makes construction of the system easier. An underground generator is used for the conversion of energy and pumping of water back to the upper reservoir during low energy demand, and can significantly reduce the noise level. The system can be used to provide significant levels of power during peak power demands, when other power supplies are more expensive and require power to operate. The system components fit the landscape esthetically, which allows the use of the system in a residential area.
U.S. Pat. No. 4,132,901 describes a power generation system suitable for terrain located in an elevated position, where there is not sufficient water supply for power generation. The shortage of water is covered by the reservoir, which is located in an elevated position, and a system of pumps for pumping water into the tank. Devices that operate on the principle of wave motors for pumping of water up from the sea level are used as pumps.
JPH11247164, publ. 14 Sep. 1999, discloses an underground system of a pumped-storage power plant for desalination and the use of salt water. The system comprises a vertical shaft extending vertically downwards from the sea level, and a second vertical shaft extending from the upper reservoir. A pipe with the reverse osmosis membrane is installed in the middle. Fresh water is produced from seawater and is stored in an underground tank. Then the water is pumped during off-peak time and is stored in the upper reservoir. During peak demand, the energy is generated by discharging the water back into the underground reservoir.
For example, application RU2011122189, publ. 10 Dec. 2012 describes a pumped-storage wind power plant, which includes an upstream pond, a water intake, a penstock, at least one irreversible hydro generator pair consisting of a hydraulic turbine, a power generator and a coupling between them, and a suction tube to drain used water in the storage downstream reservoir for its transfer to the upstream pond and re-circulating it through water turbine. On the bank of the downstream accumulative reservoir or on a platform above the surface of the water at an optimal distance from the upstream reservoir dam to prevent interference with wind flow, there is at least one hydraulic pump with a wind turbine that is installed in order to convert the wind energy into potential energy of the water column by pumping it from the downstream accumulative pond into the upstream pond, so as to pass again through the turbine-generator pair.
WO2010060504, publ. 03.06.21010, describes a system and method for energy storage. The system includes at least one storage tank for seawater, which is located above the sea level in the vicinity of the seashore. At least one turbine is located in close proximity to the sea level—significantly below the level of the storage reservoirs. The turbine is connected to a power generator. At least one channel connects the reservoir and the turbine, in which a downward flow of sea water from the reservoir causes rotation of the turbine for power generation. The publication also describes methods for prevention of corrosion and accumulation of marine organisms in the system. The system may be fully or partially powered by intermittent renewable sources of energy such as wind.
RU2353797, publ. 27 Apr. 2009, describes a system of floating pumps (a field of pumps), which includes floating pumping units, assembled so as to feed fluid in the reservoir under the influence of the waves in the ocean. The reservoir is located on top of a cliff and takes the water pumped from the floating pumping units through the discharge line. Water can be accumulated in the reservoir and flow through the outlet flow line to the turbine (turbines) arranged in the engine room. Water can be discharged back into the ocean through a discharge line. In another embodiment, the reservoir may be located above the water space, i.e. on a ship or oil platform. By minimizing the amount of energy extracted from every wave, each float pump unit disposed in the pump field receives substantially the same amount of energy.
Regardless of the nature of used natural phenomena, all of them are not entirely predictable and generally do not coincide in time with the peaks of power networks' needs for energy. The current level of progress makes the storage of electricity expensive both financially and physically: mechanical accumulators of flywheels type spend part of the energy for the friction, the chemical elements involve environmental damage due to mining and production of their components, and batteries have non-zero self-discharge currents. The most effective way to store energy for future use for a long time is the use of physical laws: change and storage of the working fluid under pressure (pneumatic pressure accumulators used in transport), and the use of the gravitational force (pumped—storage power plants—PSPP).
PSPP in the classic version has a reservoir, in which it accumulates water for its work at a time when electricity is the least in demand, and produces electricity when it is needed for electricity grid. The downside of classic PSPP is that they consume electricity from the power grid to supplement the supply of water in the reservoir.